Spray device and method



Jan. 9, 1962 M. F. BOEHM 3,016,200

SPRAY DEVICE AND METHOD Filed ug. 11, 1959 flNu a2 J/M \g I INVENTOR.

Nd): F 5024/?! ArwPm-Y 3,016,200 SPRAY DEVICE AND METHOD Max F. Boehm, Rte. 3, Box 431, Oklahoma City 7, Okla. Filed Aug. 11, 1959, Ser. No. 833,078 3 Claims. (Cl. 239--143) This invention relates generally to improvements in power spraying devices, and more particularly, but not by way of limitation, to a method of continually agitating spray solutions during the spraying procedure.

Patented Jan. 9, 1962 Another object of my invention is to provide a means of spray equipment agitation which will facilitate easy Many liquids requiring application by spraying processes are either colloids or emulsions. years particularly, a great number of new chemicalsv have been developed whose application requires the use of a spraying process which must 'be' sprayed as colloids or emulsions. ing herbicides and ground sterilants, most of which must be sprayed over the area to be treated in order to be effective.

Most ground sterilants, as an example, must be hydrophobic chemicals. ground where destruction of vegetation is required, they would soon be leached away by the action of rain waters. The application of ground sterilants requires that they be sprayed onto the area to be treated in an economic base medium such as water. Thus, a spraying system must be provided, which will spray normally oil soluble, hydrophobic suspensions. To achieve uniform applications of these hydrosols, homogeneity must be maintained in the liquid at alltimes during the spraying process.

Within recent Much work has been concentrated in perfectindicates a tank which serves to retain a supply of liquid Otherwise, after application to the Many other chemicals which are best applied by the spraying process are also colloids. A number of insecticides are specifically made oil-soluble so that residue left by the spray will not be quickly washed away by rain or irrigation water. These chemicals also require a means to maintain colloidal suspension during the spraying process. In some instances emulsifiers or'dispersants have been used. Economics and harmful effects to vegetation, however, have limited their use.

Some materials which are applied by spraying are emulthe sprayer in a level position while'in operation.

cleaning of the spraying equipment.

These and other objects of my invention may be better understood by referring to the accompanying specifications and claims taken in conjunction with the drawings in which:

FIGURE 1 is a side elevational view of the complete spraying device; 1

FIGURE 2 is a top view of the complete spraying device, and

FIGURE 3 is a sectional view of the interior bottom of the tank taken along the line 3-3 of FIG. 1, with the wheels and brace structure not shown.

Referring first to FIG. 1 and FIG. 2, the'nurneral 10 and also serves asthe main structural member by which other components are supported. The configuration of tank 10 is such, with sloping end walls 12 and 14, that the cross'sectional area of the bottom 15 is relatively small when compared to the remaining horizontal areas of tank 10. Wheels 16, supported by'axle 17 are provided for portability of the sprayer. A brace structure 18 supports A handle 20 is conveniently provided for use in moving the sprayer.

A positive displacement compress 22 is mounted on tank 10. A gasoline engine prime mover 24 is also mounted on-tank 10. A drive pulley 25 is afiixed to the drive shaft of the engine 24 whereby power is delivered to the compressor 22 by belt 26 and compressor pulley I loaded valve 30. An input extension tube 32 consions, paint being a very common example. In order to preserve homogeneous interspersing of such emulsions, the liquid must be constantly agitated during the spraying operation.

One means of agitating during the spraying process consists in the mechanical actuation of a paddle, or groups of paddles, in the liquid. Another means is the use of a rotating propeller to stir the liquid. In some instances, these methods are satisfactory; however, they have some disadvantages. arrangements to actuate paddles or to rotate propellers is relatively expensive compared to the cost of customary spraying equipment. Most spraying equipment includes a compressor actuated by an electric motor or gasoline engine. To actuate a paddle or propeller requires an additional power source or an expensive gear arrangement associated with the compressor power source.

Many chemicals which must be sprayed are corrosive to metals. Mechanical paddles and propellers therefore require a great deal of maintenance and upkeep. The

spraying equipment also must be kept clean. With'exist- To provide separate mechanical power;

This is best shown in FIGURE 3.

exceed a predetermined amount.

nectsto piping 29 to convey the compressed air into the tank 10. The input tube extends near the tank bottom 15 and terminates with a curved partial volute portion 34. By action of the curved portion 34 the discharged air tends to flow in a circuitous path near the tank bottom 15 indicated by the arrows in FIG. 3.

A discharge tube 36 extends from near the bottom 15 to the top of the tank 10 where connection is made with spray piping 37. The lower end of tube 36 is preferably positioned at a point about which the tube portion 34 is bent, as illustrated in FIG. 3. A flexible hose 38 connects to piping 37 and a spray nozzle 40. An adjustable valve 41 is inserted in the hose piping 37 whereby the volume of liquid passing to the spray nozzle 40 may be varied.

A relief valve indicated at 42, is placed in the top of the tank 10 so that air pressure within the tank will not A hand valve 44 is provided so that air compressed within the tank'may be discharged to the atmosphere when necessary. A gauge v Operation The operator first places the material to be sprayed, as for instance an insecticide, in the tank 10, followed by a suificient amount of water or other liquid vehicle. The cover 48 is next hermetically secured over opening 46.

The engine 24 and compressor 22 are started. The

spring loaded back pressure valve 30 is set at a relatively high pressure-about 500 pounds per square inch in practice. In the first few seconds of compressor operation, no air passes through back pressure valve 30 into tank because sufiicient pressure has not accumulated to force the back pressure valve 30 open. However, after a few strokes, approximately three or four in practice, the compressor 22 builds up air pressure in the outlet piping 29 between the back pressure valve 30 and the compressor 22 which acts as a small reservoir to force the back pressure valve 30 open. This permits a sudden burst of air from this small reservoir, discharging through tube 32 into the tank 10. When back pressure valve 30 opens, the air pressure is immediately reduced in. the outlet piping 29 between the back pressure valve '30 and the compressor 22. The spring tensionin the back pressure valve 30 will then force it to close. The back pressure 'valve 30 will stay closed for a few more strokes of the compressor 22 until sufficient pressure is again accumulated to open it. Thus a continuous alternating series of bursts of high pressure air is discharged into the tank 10 from tube 32.

The relief valve 42 will remain closed until the pressure in the tank 10 reaches a predetermined point desired as the optimum spray pressure, about 110 pounds per square inch in practice. If the spray nozzle .40 does not discharge air as fast as it is pumped into the tank 10, the pressure will gradually accumulate within the tank 10. After the pressure within the tank 10 reaches the mode termined set pressure of the relief valve .42,.it will open discharging air to the atmosphere. Obviously, pressure within the tank 10 will therefore never exceed this predetermined amount. Thus, when back pressure valve 30 opens, air will be discharged from a pressure of about 500 pounds to a pressure in the tank 10 never exceeding about 110 pounds. Air discharging from tube 32 will be a continuous series of sudden bursts. This processof releasing continuous bursts of air pressure violently agitates the liquid in-the tank 10. This turbulent, ebullient action of high pressure air entering the tank 10 serves to maintain colloid and emulsion liquids in a completely interspersed, homogeneous state.

The tube lower portion 34, being bent to discharge the air at the periphery or outer edge of the tank bottom 15, establishes a circuitous movement of the total liquid contained in the tank 10. This continuous motion of the spray liquid helps prevent settling which might otherwise take place.

Air supplied by compressor 22, through outlet piping 29, back pressure valve 30' and tube 32 serves two functions. First, to agitate the fluid in the tank and second to deliver air under pressure to force the spray liquid out through discharge tube 36, pipe 37, adjustable valve 41, hose 38 and spray nozzle 40 where it can be directed as required by the operator.

It can be seen that the method of agitation of this invention is readily adaptable without proportionally large expense to most Sprayers. The tube 32 can be easily and inexpensively made of materials such as brass or stainless steel which are not ordinarily subject to corrosion. The problem of corrosion encountered in the use of paddles, propellers or other mechanical means of agitation is thereby eliminated. In one embodiment, bottom portion is of circular cross section adjacent sloping side portions 12 and 14, while outlet pipe 29 is attached tangentially from the outside near the bottom.

The tube 32 and discharge tube 36 can be readily removed, leaving the interior of the tank 10 free of obstacles, making cleaning of the tank 10 much simpler.

A spring loaded back pressure valve 30 is shown in this disclosure as the means selected to control the intermittent discharge of high pressure air into the liquid. It is obvious that other means exist by which the intermittent discharge of high pressure air may be obtained. One example would be a valve which is mechanically opened and closed. It is therefore not intended to limit this dis closure to the use of spring loaded back pressure valves 30 as a means of achieving fluid agitation.

Various air pressures have been indicated in this disclosure by way of examples. It is understood that the principles of this invention are not predicated on particular pressures, nor particular ranges of pressures, but concern primarily the discharge of air from a greater to a lesser pressure as a means of achieving agitation of spray liquid. Nor is it intended to limit the principles of this invention to the agitation of spray liquids only, but to include the agitation of fluids in general.

Although this invention has been described in a certain degree of particularity, it is manifest that many changes may be made in the embodiment of the prin ciples of this disclosure without departing from thespirit and scope of the invention as set forth in the appended claims.

I claim:

1. In a liquid spraying device having a confined tank containing said liquid, an air compressor, outlet piping extending from said compressor into said liquid, spray piping and a nozzle extending from said liquid to the outside of said tank, the improvement for agitating said liquid, comprising a back pressure valve interposed in said outlet piping, biasing means in said valve for closing said valve against the passage of compressed air from said compressor until the pressure of air in said outlet piping upstream from said valve has become substantially higher than the pressure required to cause air to flow from said compressor into said tank.

2. A liquid spraying device comprising a pressure tank having side walls tapering inwardly toward a fiat bottom portion; a compressor; an engine drivingly connected to said compressor; outlet piping extending from said compressor for conveying compressed air therefrom; a spring-loaded valve on the end of said piping, the resiliency and response time of the spring of said valve being such that air from said compressor is alternately stored in and released from said outlet piping in a short burst and under high pressure; extension pipingextending from said valve means into said tank and terminating substantially parallel to said flat bottom portion and adjacent thereto in a volute; spray piping and a nozzle extending from a point in said liquid centrally located with respect to said volute to a point outside said tank; and a pressure relief valve in said tank set at a substantially lower pressure than said spring-loaded valve.

3. A device to agitate a liquid comprising in combination, a compressor; an engine for driving said compressor; a reservoir connected to said compressor for receiving compressed air from said compressor; tube means connected to said reservoir and extending into said liquid; and an interrupting means interposed between said tube means and said reservoir whereby flow of said compressed air is interrupted, said interrupting means including a spring loaded baok pressure valve.

References Cited in the file of this patent UNITED STATES PATENTS 688,261 Parks Dec. 3, 1901 1,907,086 Nason May 2, 1933 1,998,217 Benoit Apr. 16, 1935 2,424,468 Keathley July 22, 1947 2,492,309 Miller Dec. 27, 1949 2,504,009 De Phillips et al. Apr. 11, 1950 2,720,342 Fleck Oct. 11, 1955 2,923,440 Ve Horn Feb. 2, 1960 FOREIGN PATENTS 22,212 Australia Feb. 4, 1936 

